docs: def to_json(obj, indent=4, sort_keys=True, **kwargs):
      """
      :param obj: object to convert to dictionary and then output to json
      :param indent: indent json by number of spaces
      :param sort_keys: sort json output by key if true
      :param kwargs: arguments to pass to to_dict
      :return: json string
      """
      obj_dict = to_dict(obj, **kwargs)
      return json.dumps(obj_dict, indent=indent, sort_keys=sort_keys)